| 1 | H & T Brock Oil Company LLC | Comanche, OK 73529-7140 | Oil & Gas Operator | Feb 2024 |
| 2 | H G & G Inc | Edmond, OK 73034 | Oil & Gas Operator | Jan 2006 |
| 3 | Hadco LTD | Ardmore, OK 73401-6929 | Oil & Gas Operator | Mar 2015 |
| 4 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 5 | Hadson Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 6 | Haines Oil Company | Sulphur, OK 73086 | Oil & Gas Operator | Oct 2009 |
| 7 | Hall Energy Company LLC | Oklahoma City, OK 73120-5020 | Oil & Gas Operator | Jul 2022 |
| 8 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 9 | Hamil Oil & Gas LLC | Kingfisher, OK 73750-6500 | Oil & Gas Operator | Jul 2025 |
| 10 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 11 | Hamilton Properties & Investments L.L.C. | Ada, OK 74820 | Oil Operator | Jun 2025 |
| 12 | Harding & Shelton Inc | Oklahoma City, OK 73104-2410 | Oil & Gas Operator | Jun 2025 |
| 13 | Hat-Top Production Co | Duncan, OK 73533 | Oil Operator | Apr 2011 |
| 14 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 15 | Hays Production LLC | Velma, OK 73491 | Oil & Gas Operator | Jun 2025 |
| 16 | Hazelwood Prod & Exp Co LLC | Oklahoma City, OK 73116-9037 | Oil & Gas Operator | Jun 2025 |
| 17 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 18 | Heartlands Development Co Inc | Bristow, OK 74010-3826 | Oil & Gas Operator | May 2017 |
| 19 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 20 | Henderson Fred J | Okmulgee, OK 74447 | Oil & Gas Operator | Jun 2025 |
| 21 | Henry Petroleum Inc | Oklahoma City, OK 73162-1757 | Oil & Gas Operator | Sep 2019 |
| 22 | Henry Petroleum Of Oklahoma LP | Midland, TX 79703-5000 | Oil & Gas Operator | Feb 2017 |
| 23 | Hep Oil Company LTD | Gainesville, TX 76240 | Oil & Gas Operator | Mar 2012 |
| 24 | Hep Oil GP, LLC | Gainesville, TX 76241 | Oil & Gas Operator | Mar 2015 |
| 25 | Hess Corporation | Houston, TX 77010 | Oil & Gas Operator | Aug 2017 |
| 26 | HMD Oil Co Inc | Ardmore, OK 73401-2542 | Oil & Gas Operator | Jul 2025 |
| 27 | Hoard John L Family Trust | Ardmore, OK 73402-1706 | Oil & Gas Operator | Jun 2022 |
| 28 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Jul 2025 |
| 29 | Hogback Exploration Inc | Fort Smith, AR 72916 | Oil & Gas Operator | Jul 2025 |
| 30 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 31 | Holt Andrew L "Mickey" | Pawhuska, OK 74056 | Oil & Gas Operator | Aug 2008 |
| 32 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 33 | Hooks Dwain | Tatums, OK 73487 | Oil & Gas Operator | Jun 2025 |
| 34 | Hovas Enterprises | Perkins, OK 74059 | Oil & Gas Operator | Mar 2014 |
| 35 | Howard & Taylor | Wynnewood, OK 73098-9234 | Oil & Gas Operator | Jun 2025 |
| 36 | Hub-Hill Inc | San Antonio, TX 78230 | Oil Operator | Nov 1998 |
| 37 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Oct 2025 |
| 38 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 39 | Hull Oil Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Sep 2021 |
| 40 | Hulsey Larry O & Co | Graham, TX 76046 | Oil & Gas Operator | Jun 2012 |
| 41 | Hunt Chris Water Hauling Contractor Inc | Keyes, OK 73947-0004 | Oil Operator | Jun 2008 |
| 42 | Hunt Engineering Inc | Norman, OK 73069-4093 | Oil & Gas Operator | Feb 2019 |
| 43 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 44 | Hunton Oil & Gas Corporation | Oklahoma City, OK 73154-0191 | Oil & Gas Operator | May 2019 |
| 45 | Hyperion Energy LP | Dallas, TX 75206 | Oil & Gas Operator | May 2014 |